Rotorcraft Lateral-Directional Oscillations: The Anatomy of a Nuisance Mode
Rotorcraft Lateral-Directional Oscillations: The Anatomy of a Nuisance Mode
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DOI：
10.4050/jahs.66.042009
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发表时间：
2021-07
影响因子：
1.5
通讯作者：
Dheeraj Agarwal;Linghai Lu;G. Padfield;M. White;N. Cameron
中科院分区：
文献类型：
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作者：
Dheeraj Agarwal;Linghai Lu;G. Padfield;M. White;N. Cameron
高保真的旋翼机飞行模拟依赖于高质量飞行模型的可用性，这进一步要求对气动耦合和干扰效应引起的复杂性有很好的了解。一个这样的例子是在仿真中难以预测旋翼机横向振动(LDO)模式的特性。实现这种模式的可接受的阻尼水平是一个设计挑战，需要具有足够逼真度的模拟模型来揭示不稳定效应的来源。本文的重点是使用利物浦的FLIGHTLAB Bell 412仿真模型和国家研究委员会(加拿大)先进系统研究委员会的裸体飞机的飞行中LDO测量，使用系统识别来突出此类保真度问题。对仿真模型进行了改造，提高了模型的逼真度。结果表明，所识别的模型与飞行试验的LDO振型频率和阻尼值吻合较好。将识别的稳定性和控制导数与仿真模型预测的稳定性和控制导数进行比较，突出了保真度较好和较差的区域。
High-fidelity rotorcraft flight simulation relies on the availability of a quality flight model that further demands a good level of understanding of the complexities arising from aerodynamic couplings and interference effects. One such example is the difficulty in the prediction of the characteristics of the rotorcraft lateral-directional oscillation (LDO) mode in simulation. Achieving an acceptable level of the damping of this mode is a design challenge requiring simulation models with sufficient fidelity that reveal sources of destabilizing effects. This paper is focused on using System Identification to highlight such fidelity issues using Liverpool's FLIGHTLAB Bell 412 simulation model and in-flight LDO measurements from the bare airframe National Research Council's (Canada) Advanced Systems Research Aircraft. The simulation model was renovated to improve the fidelity of the model. The results show a close match between the identified models and flight test for the LDO mode frequency and damping. Comparison of identified stability and control derivatives with those predicted by the simulation model highlight areas of good and poor fidelity.